Stable isotope Promethium (Pm)

Isotope Atomic Mass Half-life Mode of Decay Nuclear Spin Nuclear Magnetic Moment
Pm-143 142.910928 265 days EC to Nd-143 5/2 3.8
Pm-144 143.912586 360 days EC to Nd-144 5 1.7
Pm-145 144.912743 17.70 years EC to Nd-145; α to Pr-141 5/2 No data available
Pm-146 145.914693 5.53 years EC to Nd-146; β- to Sm-146 3 No data available
Pm-147 146.915134 2.6234 years β- to Sm-147 7/2 2.6
Pm-148 147.91747 5.37 days β- to Sm-148 1 2.0
Pm-149 148.918330 2.212 days β- to Sm-149 7/2 3.3
Pm-150 149.92098 2.68 hours β- to Sm-150 1 No data available
Pm-151 150.92120 1.183 days β- to Sm-151 5/2 1.8

Properties of Promethium

Name Promethium
Symbol Pm
Atomic number 61
Atomic weight 145
Standard state Solid at 298 °K
CAS Registry ID 7440-12-2
Group in periodic table N/A
Group name Lanthanoid
Period in periodic table 6 (Lanthanoid)
Block in periodic table f-block
Color Metallic
Classification Metallic
Melting point 1100 °C
Boiling point 3000 °C
Vaporization point 2460 ºC
Thermal conductivity 15 W/(m·K)
Electrical resistivity About 75 x 10-8 Ω·cm
Heat of vaporization 290 kJ·mol-1
Heat of fusion About 7.7 kJ·mol-1
Density of solid 7.26 g/cm3
Electron configuration [Xe]4f56s2
Ionic radius Pm3+: 0.98 Å
Oxidation state +3